The present invention relates to an apparatus for installing a tension coil spring to be installed under tension and, more particularly, to an apparatus for installing a tension coil spring under tension between the discharge electrode wires of a rigid-frame type electrostatic precipitator.
In the operation of an electrostatic precipitator, a gas laden with entrained particulate material is passed through an electrostatic field established about a discharge electrode disposed between two grounded collector electrodes. The suspended particles become electrically charged as they pass through the electrostatic field and move, under the influence of the electrostatic field, to and deposit upon the grounded collection electrodes flanking the discharge electrode.
Typically, each collecting electrode is formed of one or more elongated plates disposed in a row side by side and suspended from top of the precipitator housing in a vertical plane. A plurality of such collecting electrodes are disposed transversely across the precipitator casing in spaced vertical planes parallel to the direction of the gas flow through the precipitator.
In what is commonly referred to as a rigid-frame electrostatic precipitator, a box-like framework comprised of a plurality of discharged electrode frame is suspended from insulators at the top of the precipitator housing to provide a row of vertically disposed discharge electrodes between adjacent collecting electrodes across the width of the precipitator. A voltage is applied to discharge electrodes to demonstrate the electrostatic field.
Each discharge electrode frame is comprised of a plurality of individual discharge electrode wires tautly strung across a support frame. As electrode wires are installed at ambient temperature but typically operated at temperatures in the range of 150 C. to 250 C., the discharge electrode wires may elongate due to thermal expansion and therefore become loose. Discharge electrode wires may also become loose due to handling during erection and shipment of the discharge electrode frames.
Although a loose wire will not impede the dust collection process per se, a loose discharge electrode wire will not respond well in a rapping process. It is typical to periodically rap the discharge electrode frame to vibrate off any dust collecting on the discharge electrodes as the collection of dust thereon can lead to arcing between the discharge electrode and its neighboring collecting electrodes or even grounding by a bridging of the collected dust between the discharge electrode wire and its neighboring collecting electrodes. A loose discharge electrode wire, however, will not vibrate as well as and, therefore not clean as easily as, a properly taut discharge electrode wire.
One method of preventing discharge electrode wires from becoming loose is disclosed in Assignee's Ser. No. 480,971, Mar. 31, 1983 now Pat. No. 4,502,872, issued Mar. 5, 1985, entitled "Discharge Electrode Wire Assembly For Electrostatic Precipitator". As disclosed therein, tension coil springs are installed to extend perpendicularly between a pair of adjacent discharge electrode wires to maintain the discharge electrode wires in a taut condition. The coil springs serve to take up any looseness in the discharge electrode wires in a direction perpendicular to the electrode wires. If two neighboring discharge electrode wires become loose during operation, a tension coil spring can be installed between those two discharge electrode wires to restore both of the loose wires to their original tautness. Also, a tension coil spring may be installed between a loose wire and a neighboring tight wire to restore the loose wire to its original tautness without effecting the already tight wire.
On discharge electrode wires that are within arms reach of access platforms installed in the precipitator at either end of the collection chamber, the tension coil springs can be installed by hand with relative ease if those wires are within arms reach. However, it is very difficult for a workperson to get between rows of collecting electrode plates to install springs on discharge electrode wires out of arms reach of the ends of the collecting chamber.
Therefore, it is an object of the present invention to provide an apparatus for installing tension coil springs under tension at locations out of arms reach. More particularly, it is an object of the present invention to provide an apparatus particularly adapted for installing tension coil springs between the discharge electrode wires disposed within a rigid frame-type discharge electrode assembly located out of arms reach of the end of the assembly.